The subject matter of the invention is a new process for the production of N-acetyl-2,3-dehydro-aminocarboxylic acid esters of the general formula: ##STR1## in which R.sup.1 is a methyl or ethyl group, R.sup.2 is hydrogen or a methyl group and R.sup.3 is hydrogen, an alkyl group having 1 to 6 carbon atoms, an aryl group, an unsubstituted or substituted alkylmercapto group, e.g. the alkyl group has 1 to 6 carbon atoms, or an arylmercapto group.
Compounds of the general formula (I) are known. They serve chiefly as intermediate products for the production of optically active 2-N-acetylaminocarboxylic acids by asymmetrical catalytic hydrogenation of the prochiral C.dbd.C double bond.
It is also known already to produce N-acetyl-2,3-dehydro-aminocarboxylic acid esters in a two-step process by reaction of 2-azido-carboxylic acid esters with n-butyl-lithium/ethanol and subsequent acylation with acetyl chloride, (Manis et al, J. Org. Chem. Vol. 45 (1980), pages 4952-4954). In this manner there can be produced, for example, the N-acetyl-2,3-dehydro-alanine ethyl ester in a yield of 58% of theory.